This is a controversial take for anyone who's not been an author for at least a couple of years.
I get emails, DMs, messages of all kinds. Sometimes, it's just a simple thank you note and I mostly answer those back; I'll probably continue doing so unless I get overwhelmed by it.
What I do not do is engage in lengthy conversations. I have had terrible experiences, a couple close to stalking. I have met fans in real life multiple times while writing my Italian novels and it’s mostly been pleasant. However, since Even the most loyal reader finds it hard to remember that you are just a normal person, I prefer remaining detached from my audience unless I really connect with the person.
I’m not haughty nor do I consider myself better than my readers, it’s simply part of How I keep my life stress free. You can sum it up as if we could go along as friends outside the writing/reading world, then I'll respond amicably. If I don't like the person that much, I'll try to stay as distanced as possible, while keeping up with politeness.